Conventionally, a map updating method is known which automatically detects a road not present in map data, updates the map data at necessary timing, and offers to a user as common map data (see Patent Document 1, for example). In the technique disclosed in Patent Document 1, when a vehicle loaded with a navigation apparatus travels a new road not present in map information of the navigation apparatus, the traveled course by the vehicle is transmitted to a map information providing apparatus. If the map information providing apparatus finds the road corresponding to the traveled course in its map information, it transmits the map information to the navigation apparatus. The navigation apparatus updates the map information it possesses up to that time to the map information received from the information providing apparatus, thereby obtaining the map information including the new road.
In addition, a Patent Document 2 discloses a dynamic map data updating system that is configured in such a manner as to enable a navigation apparatus to display the latest update map data via a downlink. The technique disclosed in the Patent Document 2 detects that the vehicle loaded with the navigation apparatus travels a new road not included in the map data file of the navigation apparatus from a failure of map matching, and transmits its traveled course to the map information providing apparatus. The map information providing apparatus searches accumulated route information for the route information corresponding to the received traveled course, and sends the route information found back to the navigation apparatus. The navigation apparatus displays the route information sent back as a new road.
Patent Document 1: Japanese Patent Laid-Open No. 2001-194163.
Patent Document 2: Japanese Patent Laid-Open No. 2000-258176.
However, in the technique disclosed in the foregoing Patent Document 1, since the navigation apparatus uses the map information by downloading it from the map information providing apparatus, if the data format of the map information of the navigation apparatus differs from that of the map information of the map information providing apparatus, the navigation apparatus cannot use the map information it downloads from the map information providing apparatus, and this presents a problem of being unable to update the map information.
In addition, as for the navigation apparatus disclosed in the foregoing Patent Document 2, since it cannot update the map data file using the route information sent back from the map information providing apparatus, it has a problem of being unable to add the new road to the map data file. Furthermore, although the vehicle detects that it travels a new road not included in the map data file from the failure of the map matching, since the map data file used for the map matching is not updated as described above, the navigation apparatus has a problem in that it must acquire the same route information from the map information providing apparatus every time it travels the same road not included in the map data file.
The present invention is implemented to solve the foregoing problems. Therefore it is an object of the present invention to provide an onboard information terminal and map information providing apparatus and map information providing system using them capable of updating the map data independently of the data format of the map information.